Diesel engines produce a number of combustion products including particulates, hydrocarbons (“HC”), carbon monoxide (“CO”), oxides of nitrogen (“NOx”), and oxides of sulfur (“SOx”). Future diesel engines will likely require exhaust aftertreatment systems to reduce emissions of these and other products of combustion. Such exhaust aftertreatment systems may include a number of components including catalytic conversion components, particulate filters, and others which can be operated in a variety of modes. In addition to base modes of operation, from time to time it may be necessary to implement regeneration modes which regenerate various components of exhaust aftertreatment systems. There is a need for apparatuses, systems and methods of flexible fuel injection in the foregoing and other modes.